Precision pipe advancement mechanism for bending machine



F. H. KELLEY 3,009,508

EEEcIsIoN PIPE ADVANCEMENT MECHANISM EOE BENDING MACHINE 3 Sheets-Sheet l Nov. 21, 1961 Filed March 3, 1958 Nov. 2l, 1961 Filed March .3, 1958 F. H. KELLEY PRECISION PIPE ADVANCEMENT MECHANISM FOR BENDING MACHINE 5 Sheets-Sheet 2 Arm NEK Nov. 21, 1961 F. H. KELLEY 3,009,508

PRECISION PIPE ADVANCEMENT MECHANISM FOR BENDING MACHINE Filed March 3, 1958 3 Sheets-Sheet 3 l WQ 250 206 2% 22 22@ /54 /f 220 202 iin-e dce 3,ttl9,5t8 PRECISION PIPE ADVANCEMENT MECHANISM FOR BENDING MACHlNE Forrest H. Kelley, Rte. 1, sceola, Mo. Filed Mar. 3, 1958, Ser. No. 718,836 11 Ciaims. (Cl. 153-48) This invention relates to an improved machine for bending pipes, conduits, bars and similar articles and has for its primary object to pro-vide precision mechanism for advancing such articles through suitable bending apparatus.

Various types of pipe bending machines have been previously provided but the same have not been entirely satisfactory because they were either too complicated in design and operation or incapable of accurately advancing the pipe through the bending apparatus so that the desired degree of bend was obtained. The present mechanism has particular utility in the field of electrical conduits wherein it is necessary to bend co-nduits which are supplied in standard lengths, it being necessary to not only bend such conduits at predetermined angles but also in a manner so that the outer end of the bent portion terminates in predetermined spaced relationship to the unbent length of the pipe. As referred to above, electrical conduits are commercially supplied in standard lengths such as ten feet and during construction operations, it is necsary to bend the conduits into specified configurations for meeting the specifications of the building being constructed. Conduits of the type described are often several inches in diameter and a problem is presented in attempting to bend such conduits without forming of dimples or eggs in the surface thereof.

The prior pipe bending machines have generally utilized a reciprocable shoe adapted to be shifted toward a pair of spaced structures supporting a pipe so that as the shoe is moved toward the structures, the pipe is bent therebetween. However, because of the size of the conduit, in order to bend the conduit to a required degree, it is ordinarily necessary -to direct the shoe against the pipe at a plurality of spaced intervals along the length thereof so that the angle of bend at each shot is relatively small. It has been determined that for relatively Ilarge electrical conduits, the movement of the pipe at each shot must be below one and one-half inch to prevent formation of the dimples and eggs described above.

Heretofore the standard procedure in bending of electrical conduits has been to determine the degree of bend desired and the radius of the bend so that the number of shots necessary for bending without deformation of the pipe may be calculated. The number of shots are marked on the outer surface of the pipe with a pencil and it can be readily perceived that errors can very easily occur during such marking because of the fact that the shots are normally divided into thousandths of an inch. Because of this highly inaccurate procedure, it has been the usual practice heretofore to attempt to get the degree of bend with the required radius as close as possible and then cut off either one or both ends of the pipe on each end of the bend so that the specified length of pipe is obtained. This, of course, is extremely costly because of the conduit wastage and the fact that very often conduits must be discarded in their entirety because the bend was not of the proper degree with the required radius. The problem is further complicated by the fact that the bending must be carried out as fast as the workmen place the conduits in place and thus, the whole construction operation has been heretofore seriously impaired by the failure to provide a satisfactory method of bending electrical conduits at the same rate that the same may be mounted in position on the building.

It is, therefore, an important object of this invention to provide mechanism for advancing pipe through pipe ybending apparatus in a manner so that the pipe is bent at a predetermined degree of bend, at a designated radius, and with the outer end of the pipe at a specified distance from the longitudinal length thereof remaining unbent without in any manner causing deformation or adverse effects on the pipe during such bending.

An equally important object of this invention is to provide precision pipe advancing mechanism for bending machines wherein the mechanism includes components for advacing the pipe through the bending apparatus at predetermined, exactly equal increments which are accurate to one thousandth of an inch.

Another important object of 'the present invention is to provide precision pipe ladvancing mechanism as referred to above which includes shiftable structure for supporting a pipe to be bent in a position to be received within pipe bending apparatus, and including means connected with the structure for intermittently shifting the latter and, thereby, the pipe toward the apparatus in predeterminend increments whereby the pipe may be bent at spaced intervals along the length thereof with a very high degree of accuracy.

Also an important aim of the invention is to provide pipe advancing mechanism wherein is included manuallyr operable means controlling advancement of the pipe supporting carriage toward the pipe bending apparatus, so that the interval between each period of advancement of the pipe through the apparatus may be selectively varied as desired.

A further important aim is to provide pipe advancing mechanism as described wherein the increment of movement of the pipe during each advancement -thereof may be infinitely varied within a predetermined range, to the end that bending of the pipe at the desired degree with a specified radius and with the outer end thereof disposed at a predetermined distance from the longitudinal length of the pipe remaining unbent is assured.

Other important objects of this invention relate to the provision of pipe advancing mechanism wherein is included an elongated track shiftably supporting the pipe carriage, and normally continuously rotating screw means disposed in a position so that the carriage may be operabily coupled with the screw means at any desired time and for any predetermined period, whereby the carriage and thereby the pipe may be advanced toward the pipe bending apparatus at selected intermittent intervals; to the provision of advancing mechanism including lock means adapted to engage the track supporting the pipe carriage and shiftable with respect to the carriage, to the end that mechanism carried by the lock means and the carriage is capable of interengaging the carriage with the continuously rotat-ing screw for ya predetermined period and then disengaging the carriage from the screw after the carriage has moved a predetermined distance relative to the lock-ing means releasably coupled with the carriage supporting track, whereby the carriage and the pipe may be advanced toward the bending apparatus in predetermined equal increments; to the provision of solenoid operated means for engaging and disengaging the carriage from the continuously rotating screw and for releasably coupling and uncoupling the lock means from the carriage supporting track7 and electrical control means operably connected to the solenoid operated means for selectively controlling operation of the same whereby the pipe carriage is automatically advanced toward the pipe bending apparatus at specified increments to assure bending of the pipe at predetermined spaced intervals along the Ilength thereof; and to other lesser, important objects and details of construction which will become obvious or be more fully explained as the following specification progresses.

In the drawings:

FIGURE l is a plan view of a pipe bending machine having precision pipe advancement mechanism thereon embodying the concepts of the present invention;

FIG. 2 is a side elevational View of the machine shown in FIG. l and showing the normal position of a pipe being bent in phantom;

FIG. 3 is a fragmentary, enlarged, plan view of the pipe carriage forming a part of the present advancing mechanism, with certain parts thereof being broken away to reveal details of construction;

FIG. 4 is a fragmentary, enlarged, side elevational view of the pipe carriage illustrated in FIG. 3;

FIGS. 5 and 6 are fragmentary, enlarged, Vertical, cross-sectional views taken on the lines 5 5 and 6-6 of FIG. 4 and looking in the direction of the respective arrows;

FIG. 7 is a fragmentary, enlarged, horizontal, crosssectional view taken substantially on the line 7-7 of FIG. 3; and

FIG. 8 is a schematic diagram of the wiring circuit forming a part of the present mechanism.

A pipe bending machine broadly designated by the numeral 1t) and including a frame 12 and pipe bending apparatus generally designated 14, embodies pipe advancement mechanism 16 constructed in accordance with the principles of the present invention and illustrated in the drawing in its preferred form. Frame 12 includes a substantially rectangular upper rack 18 normally supported in a horizontal position by lower structure 20 including upright legs 22 at each corner thereof having adjustable means 24 permitting the effective length of each leg 22 to be varied so that rack 18 may be positioned in a horizontal plane, regardless of the irregularity of the surface 26 upon which machine 10 is positioned.

Crossbars 28 carried by rack 1S support a rectangular track 30 which includes a pair of parallel, horizontally disposed rails 32 and 34 which extend the longitudinal length of rack 1S and are substantially coextensive in length therewith.

Means for supporting pipe bending apparatus 14 at one end of rack 18 includes a pair of spaced, upright mounting plates 36 supported in parallel relationship by a number of standards 33 secured to corresponding crossbars 2S and 4t). Pipe bending apparatus 14 includes a pair of upright, horizontally spaced, triangular supports 42 pivotally mounted on plates 36 `at corresponding apexes thereof and which serve as supports for a pair of opposed forming blocks 44 and hydraulically actuated means 46 provided with a vertically reciprocable shoe 4S disposed between blocks 44.

An elongated screw 5t) is rotatably carried by spaced bearings 52 mounted on corresponding ends 54 of track 30 with screw 5()` being disposed in a horizontal plane parallel with rails 32 and 34 and medianly positioned between the latter. A prime mover 56 mounted on rack 18 at the end thereof opposite to bending apparatus 14 is operably connected to the proximal end of screw 50 through a gear reducer 58 and a clutch 60.

Advancement mechanism 16 shiftably mounted on track 30 includes a carriage designated 61 provided with a rectangular, horizontally disposed plate 62 overlying track 30 and screw 50 and having a pair of opposed sides 64 and 66 depending from the lower face thereof and disposed in parallel relationship to rails 32 and 34. A pair of rollers 68 are rotatably mounted on each of the sides 64 and 66 adjacent the lower edge thereof and at opposed ends of the same and, as clearly illustrated in FIG. 5, rails 32 and 34 are substantially U-shaped in cross-section to present a pair of opposed legs 70 with rollers `68 being disposed between corresponding legs 70 of a respective rail 32 and 34. It can now be preceived that carriage 61 is shftable along the llongitudinal length of track 3G as rollers 63 rotate within corresponding rails 32 and 34 and support carriage 61. Structure 72 for holding a pipe 74 in a horizontal position to be received in pipe bending apparatus 14 is positioned on the uppermost face of plate 62 and includes a clamp 76 adapted for holding pipes or conduits 74 of various diameters in a horizontal position. Centering mechanism broadly numerated 78 is also carried by the upper face of plate 62 for maintaining pipe 74 in longitudinal alignment with rails 32 and 34 so that the same is directed into apparatus 14 in exact alignment with blocks 44. Centering mechanism 78 is provided with an elongated cross screw 80 rotatably mounted in spaced brackets 82 and 84 disposed on the upper face of plate 62 and rotatable receiving a pair of spaced, hexagonal collars 86, each having an upright pipe-engaging stop 88 on the upper face thereof. Screw 80 is threaded in different directions on opposite sides of bracket 82 so that as the same is rotated by turning handle 90, stops 88 are moved toward or away from each other depending upon the direction of rotation of screw 80, it being apparent that stops 88 cannot rotate with respect to screw 30 because of the interengagement of the lower flat faces of hexagonal collars 86 with the upper face of plate 62, as clearly illustrated in FIG. 7.

Means for operably interconnecting carriage 61 with screw 50 includes a pair of opposed solenoids 92 and 94 mounted on the inner faces of respective sides 64 and 66 and having corresponding, reeiprocable armatures 96 and 9S. A semicircular member 100 having a laterally extending projection 102 rigidly secured thereto and pivotally connected to the outermost end of solenoid 98 is internally threaded at 104 in a manner to complementally interrnesh with the threads of screw 5t) when member is shifted into engagement with the same. An upright block 106, pivctally connected to the outermost end of armature 96, is secured to member 100 for movement therewith by a pair of vertically spaced connecting links 1% disposed on opposite sides of screw 50.

A pair of horizontally spaced, substantially L-shaped mounts llt) and 112 are suitably secured to the outer face of side 64 by welding or the like and serve to mount locking means broadly designated by the numeral 1-14. As illustrated in FIG. 4, locking means 114 includes an elongated cylindrical rod 116 carried by mounts 110 and 112 and keyed to the latter adjacent the lowermost ends of the vertical portions of mounts and 112 and parallel to and spaced from rail 34. An elongated slcevc 113 is slidably telescoped over and keyed to rod 116 for movement with respect thereto and has an elongated, irregularly shaped bracket 120 welded to the normally uppermost surface thereof, it being apparent from FIG. 3 that the outermost end of bracket 120 extends through opening 121 in side 64 into partial overlying relationship to the upper leg 79 of rail 34. An elongated element 122 is pivotally attached intermediate its ends to the lower face of bracket 120 adjacent the `outer end of the latter. A pair of stops 1-24 and 126 are secured to the lower face of element 122, depend therefrom and are located on opposite sides of the point of pivotal interconnection of bracket 12) and element 122, it being noted that stop 124 is disposed on the inside of rail 34 while stop 126 is located on the outside thereof. A substantially L- shaped bracket 128 has a horizontal leg 130 welded to the surface of sleeve 118 away from carriage 61 and an upright leg 132 remote from sleeve 11S. A third solenoid 134 secured to leg 132 of bracket 128 has an armature 136 pivotally connected to the end of element 122 remote from stops 124 and 126 by a link 136, it being noted that the outer end of link 138 away from armature 136 is adjustably secured to element 122 by virtue of a screw 140 mounted on the outer end of element 122 and receiving the end of link 138. As shown in FIG. 3, an adjustable collar 142 is positioned over link 138 on each side of screw 140 so that the effective length of link 13S may be changed. Spring means (not shown) associated with solenoid '134 normally biases armature 136 toward the outermost end of its path of travel, while an elongated spring 146 suitably secured at one end thereof to mount 116 by a fastener 148 and to the end of leg 130 of bracket 128 remote from leg 132 by a fastener 150 biases sleeve 118 and the parts mounted thereon toward mount 11G and thereby in a direction toward apparatus 14.

A switch block 152 is secured to the upper face of leg 130 of bracket 128, extends upwardly therefrom and terminates above the upper face of p-late 62. As shown in FIG. 3, switch block 152 is spaced from and parallel with side 64 and mounts a switch 154 extending through the same and having an actuating arm 156 projecting toward side 64.

Means for actuating switch arm 156 comprises an elongated cylinder 158 secured to a shaft 160 which is threaded at one end thereof `as at 162 and is rotatably journalled in horizontally space-d bearings 164 and 166 welded to the outer face of side 64. A set collar 168 secured to the outer end of shaft 166 adjacent bearing 164 prevents relative movement of shaft 160 in a direction toward bearing 166, while micrometer means broadly designated by the numeral 170 is provided adjacent bearing 166. Micrometer means 170; includes an annular member 172 Secured to bearing 166 and receiving shaft 160, as well as an annular member 174 attached to shaft 164)y for rotation therewith and having handle means 176 thereon for facilitating rotation of member 174 and thereby, shaft 168. The outer circular surfaces of members 172 and 174 are suitably calibrated to indicate the degree of rotation of member 174 with respect to member 172. An elongated, upright stop 178 is secured to the normally upper surface of cylinder 1-58 and extends upwardly a suicient distance to engage arm 156 when switch y154 is moved to a position proximal to stop 178. Au adjustable stop in the nature of a horizontally disposed screw 179 rotatably threaded into the lower lateral leg of mount `l110l serves to limit the extent of reciprocation of Sleeve 118 toward mount 110. In this manner, the point at which stop 178 engages switch `arm. 156 to actuate switch 154 may be adjusted so that the zero numeral of the scale on member 172 moves into accurate alignment with the zero of the scale on member 174 exactly at the moment that switch 154 is actuated by stop `178.

Machine 1t)l has electrical control means broadly designated by the numeral y180 for controlling operation of rnotor 56 and solenoids 92, 94 and 134. A pair of power lines 1182 and 184 forming Ia part of control means 188 are adapted to be connected to suitable source of electrical power and la single pole, double throw manual switch 186 having a switch arm 188 connected to power line 182 by a lead 190 and a pair of contacts 192 and 194 coupled with opposite windings 196 and 198 by respective leads 280i and 282 permit selective operation of motor 56 in opposite directions. Windings 196 and 198 are electrically connected to power line 184 by a lead 204 having a single pole, single throw manual switch 286 therein for breaking the circuit to motor 56 upon opening of the same.

One lead 208 of the winding of solenoid 92 is connected to the contact 210 of a single pole, single throw manual switch 212 provided with a switch arm 214 operably coupled vvith power l-ine 182 through a lead 216. The winding of solenoid 92 is also connected to the contact 218 of a relay 220 through a lead 222, relay 220l having a coil 224 connected with power line 184 by a lead 226 and to lead 208 by a line 228 havin-g switch 154 interposed therein, with switch arm 156 positioned to engage contact 230. Relay 220 is of the single pole, double throw type and therefore, is provided with a Contact 232 in opposition to contact 218 with a pole piece 234 cou-V pled with power line 184 by a lead 236 and adapted to move between contacts 218 and 232. Contact 232 of relay 220 is electrically connected to the winding of solenoid 92 by a lead 238, while the winding of solenoid 94 is al-so operably connected with power line 182 by a lead having a single pole, single throw manual switch 242 therein which includes a switch arm 2'44 adapted to engage the contact 246 connected in lead 240. The winding of solenoid 134 is coupled with lead 208 by a line 248 and to lead 222 by a line 250 having a switch 252 interposed therein.

In operation, the operator of machine 10 determines the number of shots necessary to bend a pipe 74 in the nature of an electrical conduit or the like in the desired degree of bend `at the particular radius necessary and with the uppermost end of the bent part of the pipe terminating at a predetermined distance with respect to the longitudinal unbent length of the pipe after the bending operation has been completed. As heretofore pointed out, movement of the pipe for each shot most usually must be less than one and one-half inch to prevent deformation of the pipe when shoe 48 contacts pipe 74 between blocks 44. Therefore, the operator may readily calculate the increment of movement of the pipe for each shot in order to prevent damage to the pipe while at the same time obtaining the necessary bend in such pipe.

Knowing the exact distance which the pipe must move for each shot, the operator then turns handle means 176 a requisite number of turns to move stop 178 a predetermined distance from switch arm 156. As previously described, the outer circular surfaces of annular members 172 and 174 forming a part of micrometer means 170 are calibrated so that the exact distance of stop 178 from switch arm 156 may be accurately determined. Inasmuch as the calibrations on members 172 and 174 are in thousandths of an inch, it can be readily appreciated that the distance which it is desired to move pipe 74 for each shot may be laccurately set up on machine 10 by turning handle 176 and thereby member V174 a desired number of revolutions.

An elongated length of pipe 74 in the nature of an electrical conduit is positioned in clamp 76 so that the same extends longitudinally of rack 18 in parallelism with rails 32 and 34. Clamp 76 is brought into rtight engagement with pipe 74 and then handle 90 is turned to rotate screw 88 in a direction to move stops 88 into engagement with pipe 7 4. It can be appreciated that since stops 8S are positioned in equally spaced relationship to bracket 82, upon engagement of both of the stops 88 with pipe 74, the latter is maintained in exact parallelism with rails 32 and 34.

Carriage 61 is shifted toward pipe bending apparatus 14 until the proximal end of pipe 74 is positioned over forming blocks 44. Switch arm 188 of switch 186 is then moved into contacting relationship with contact 192 to rotate screw 5t) in a direction to move carriage 61 toward pipe bending apparatus 14 upon engagement of member with screw 50. Inasmuch as switch 206 is normally closed, it can be seen that motor 56 will be operated from power line 182 through lead 19t), switch arm 188 in engagement with contact 192, lead 200,V winding 196, switch 206, and lead 284 operably coupled with power line 184. Thus, with switch arm 188 in engagement with contact 192, prime mover 56 will be continuously 0perated to in turn rotate screw 50 about the longitudinal axis thereof through gear reducer 58 and clutch 60.

Pipe Ibending apparatus 14 is actuated to move the shoe 48 thereof toward and into engagement with pipe 74 for bending the same to a predetermined degree. Thereupon, shoe 48 is reciprocated away from pipe 74 and switch arm 214 of switch 212 is moved into engagement with contact 214i? to energize solenoids 92 and 134 through a circuit to be hereinafter traced. Immediately after manual closing of switch 212, switch 242 is also closed by moving switch arm 244 into engagement with contact 246 but solenoid 94 is not energized because energization of coil 224 of relay 220 causes arm 234 to be brought into engagement with Contact 218, thereby breaking the circuit to the winding of solenoid 94 through leads 236 and 238. As illustrated in FIG. 8, closing of switch 212 energizes the coil 224 of relay 220 through lead 216 coupled with power line 182, switch arm 214, contact 210,

accaeos lead 20S, switch 154 interposed in line 228 and lead 226 coupled with power line 184.

Energization of coil 224 of relay 220 causes the pole piece or switch arm 234 thereof Ito be moved into engagement with contact 218 to thereby effect energization of solenoid 92 through lead 216 connected with power line 132, switch arm 212 in engagement with contact 210, lead 20S, lead 222, switch arm 234 and lead 236 coupled with power line 184, while solenoid 134 is energized through the same circuit inasmuch as lead 243 is connected to lead 208 while line 250 is electrically coupled with lead 222.

Upon energization of solenoid 92, the armature 96 thereof is retracted into the same to move member 106 into intermeshing relationship with continuously rotating screw 50 so that as screw 50 rotates, carriage 61 is advanced toward pipe bending apparatus 14. As clearly indicated in FIG. 8, solenoid 134 is energized simultaneously with energization of solenoid 92, thus causing armature 136 to be retracted therewithin and pulling link 138 therewith Ito pivot element 122 about the point of attachment of the same to bracket 126 and causing stops 124 and 126 to be moved into binding engagement with rail 34. Interengagement of stops 124 and 126 with rail 34 prevents movement of sleeve 113 relative to rail 34 so that sleeve 113 and all of the components mounted thereon and including mounting plate 152, switch 154, bracket 128, solenoid 134, bracket 12) and element 122 are not permitted to shift relative to rail 34 as carriage 61 is moved toward pipe bending apparatus by continuously rotating screw 50. Inasmuch as cylinder 153 shifts with carriage 61 as the latter moves toward bending apparatus 14, stop 178 is thereby moved toward outwardly projecting switch arm 156 of switch 154. Upon contact of stop 178 with switch arm 156, the latter is moved out of engagement with contact 230 in line 228 to thereby break the circut to coil 224 of relay 22). Deenergization of coil 224 permits the arm 234 of relay 220 to be biased by suitable spring means into engagement with contact 232 to thereby break the circuits to the windings of solenoids 92 and 134 and permitting solenoid 94 to be energized through closed switch 212 in lead 240 and thence through lead 238, contact 232, arm 234, and lead 233 operably coupled with power line 134.

The armature 98 of solenoid 94 is retracted into the latter upon energization `of the same to thereby move member 100 out of operable engagement with continuously rotating screw 59 and thereby immediately discontinuing advancement of carriage 61 toward bending apparatus 14.

It can now be ascertained that carriage 61 has been advanced toward pipe bending apparatus 14 a predetermined distance, thereby causing pipe 74 to be moved therewith. Shoe 48 is again reciprocated toward and into engagement with pipe 74 to bend the same, whereupon the cycle described above may be repeated. In order to prevent the winding of solenoid 94 from being energized after member 160 has been moved away from screw 50, switch 242 may be opened after switch 212 has been opened.

Motor 56 is of the reversible type so that, if desired, the operator may return carriage 61 to the outer end of its path of travel adjacent prime mover 56 by opening switch 252 to prevent energization of solenoid 134 and then closing switch 212 to energize solenoid 92 through the circuit referred to above and thereby moving member 100 into engagement with screw 50, it being appreciated that switch arm 188 of switch 186 is thrown to a position engaging contact 194 in conduit 202 so that motor 56 is operated through winding 198 thereof. Rotation of screw S in the opposite direction manifestly moves carriage 61 toward end 54 of track 30 and away `from pipe bending apparatus 14. Switch 206 is provided adjacent the end of screw 50 proximal to prime mover 56 for stopping motor 56 as the circuit thereto is broken if carriage 61 is permitted to travel to the extreme end of its path of travel toward end 54 of track 3G.

It should be emphasized that the operator of machine 16 may quickly place the desired bend in a pipe 74 by merely calculating the distance which pipe 74 should be moved for each shot and then setting up such distance by rotating member 174 of micrometer 170 the desired amount to move stop 178 away from switch arm 156 the requisite distance. Then, the entire bending operation may be carried out by merely alternately opening and closing switches 212 and 242 as bending apparatus 14 is actuated to move shoe 48 into bending engagement with pipe 74 between each intermittent operation of carriage 61.

One important feature of the invention is the fast that intermittent shifting of carriage 61 toward bending apparaus 14 is entirely at the control of the operator so that the bending of pipe 74 may be closely controlled. Furthermore, this permits the operator to unclamp pipe 74 from structure 72 so that the pipe 74 may be rotated about its -longitudinal axis a certain degree, to the end that three-dimensional curves may be readily formed in pipe 74 if desired.

Having thus described the invention what is claimed as new and desired to be secured by Lettere Patent is:

1. In pipe advancing mechanism for a machine provided with pipe bending apparatus, a carriage for supporting a length of pipe; an elongated track shiftably supporting the carriage with said pipe disposed in a position to be received by said apparatus; an elongated screw extending longitudinally of said track; means operably coupled with said screw normally continuously rotating the same on its longitudinal axis; a threaded member mounted on said carriage and selectively complementally engageable with said screw yfor shifting the carriage and the pipe toward said apparatus as the screw is rotated; a first soienoid connected with said member for moving the latter into complemental engagement with said screw; a second solenoid connected with said member for moving the latter out of engagement with said screw; structure shiftably carried by said carriage and including lock means releasably engageable with said track whereby the carriage shifts relative to said lock means when the latter is engaged with said track; and electrical control means operably coupled with said solenoids for energizing said first solenoid upon engagement of said `lock means with the track and for subsequently deenergizing said first solenoid and energizing said second solenoid after the carriage has shifted a predetermined distance relative to said lock means whereby the pipe may be intermittently advanced to said apparatus at spaced intervals along the length thereof.

2. Pipe advancing mechanism as set forth in claim 1 wherein said track includes a pair of spaced rails and wherein said lock means includes an elongated element pivotally mounted thereon and overlying one of the rails, said element being provided with a pair of spaced stops extending laterally from one face thereof and disposed on opposite sides of said one rail whereby upon pivoting of the element in a direction to move said stops into engagement with said one rail, movement of said lock means relative to the track is prevented.

3. In pipe advancing mechanism for feeding pipe to a machine provided with pipe bending apparatus, a shiftable carriage including pipe supporting means for supporting a length of pipe in a position to be received by the apparatus; actuating means operably engageable with said carriage; and adjustable stop means on said actuating means and engageable with said carriage whereby said actuating means shifts said carriage and feeds pipe to the machine and said stop means engages with and stops said carriage after a length of pipe is fed to the machine determined by said adjustable stop means.

4. Pipe advancing mechanism as set forth in claim 3, wherein is provided control means connected with said adjustable stop means to infinitely vary the relative positioning of the adjustable means and the carriage, thereby infinitely varying the length of pipe shifted.

5. The combination with a pipe bending machine having a pipe bending shoe alternately advanceable toward and retractable from bending engagement with pipe delivered thereto of pipe advancing mechanism for feeding pipe thereto including a shiftable carriage including pipe supporting means for supporting a length of pipe in a position to be received by the machine; actuating means operably engageable with said carriage; adjustable stop means on said actuating means and engageable with said carriage; and control means connected with said stop means for infinitely varying the position of said stop means, thereby infinitely varying the length of pipe shifted toward the machine.

6. The combination of claim further including means interconnecting the shoe and said actuating means to energize said actuating means when the shoe is in the retracted position and deenergize said actuating means when the shoe is in the advanced position whereby the pipe may be bent at predetermined intervals along the length thereof.

7. 'I'he combination of claim 6 further including continuously operating drive means; said actuating means including engageable and disengageable drive responsive means coupled with said interconnecting means to engage with said drive means and drive said carriage when said actuating means are energized and to disengage with said drive means and stop said carriage when said actuating means are deenergized.

8. The combination of claim 7 wherein said drive means includes an elongated screw; said drive responsive means includes a threaded member mounted on the carriage and `complementally engageable with the screw; and said actuating means includes solenoid means connected with said threaded member,

9. Pipe advancing mechanism as set forth in claim 2 wherein is provided a third solenoid; said third solenoid operably coupled with said electrical control means to pivot said element into engagement with said one rail upon energization of said riirst solenoid and for deenergizing said third solenoid upon deener-gization of said first solenoid and energization of said second solenoid.

10. Pipe advancing mechanism as set forth in claim 9 wherein said electrical control means includes switch means carried by said lock means and adapted to be actuated by parts shiftably mounted on said carriage and disposed to engage said lswitch means to control deenergization of said first and third solenoids and energization of said second solenoid after the carriage has shifted said predetermined distance relative to said lock means; said parts shiftable to any one of an infinite number of positions within a 4selected distance to permit infinite variation of the period of advancement of said carriage toward said apparatus within a predetermined range.

11. Pipe advancing mechanism as set forth in claim 10 wherein the direction of rotation of said screw is reversible, and said electrical control mechanism includes manually operable switch means for controlling energization of said first and third solenoids.

References Cited in the tile of this patent UNITED STATES PATENTS 1,587,158 Husid June 1, 1926 2,581,082 Drissner et al Ian. 1, 1952 2,604,924 Blake et al. July 29, 1952 2,832,394 Blagden Apr. 29, 1958 

